240 UPSALA ERRATICS. chap. xui. 



when the north of Europe had ah'eady assumed that remark- 

 able feature of its physical geograj^hy, which separates the 

 Baltic from the ]^orth Sea, and causes the Gulf of Bothnia 

 to have only one-fourth of the saltness belonging to the 

 ocean. 



I cannot doubt that these large erratics of Upsala were 

 brought into their present position during the recent period, 

 not only because of their moderate elevation above the sea- 

 level in a country where the land is now rising every century, 

 but because I observed signs of a great oscillation of level 

 which had taken place at Sodertelje, south of Stockholm 

 (about fortj^-five miles distant from Upsala), after the country 

 had been inhabited by man. I described, in the " Philosophical 

 Transactions" for 1835, the section there laid open in digging 

 a level in 1819, which showed that a subsidence followed by a 

 re-elevation of land, each movement amounting to more than 

 sixty feet, had occurred since the time when a rude hut had 

 been built on the ancient shore. The wooden frame of the 

 hut, with a ring of hearthstones on the floor, and much charcoal, 

 were found, and over them marine strata, more than sixty 

 feet thick, containing the dwarf variety of Jlytilus edulis, and 

 other brackish-water shells of the Bothnian Gulf Some vessels 

 put together with wooden pegs, of anterior date to the use of 

 metals, were also imbedded in parts of the same marine form- 

 ation, which has since been raised, so that the upper beds 

 are more than sixty feet above the sea-level, the hut being thus 

 restored to about its original position relatively to the sea. 



"We have seen in the account of the Danish <' shell-mounds," 

 or ''refuse-heaps," of the recent period (p. 13), that even at 

 the comparatively late period of their origin the waters of 

 the Baltic had been rendered more salt than they are now. 

 The Upsala erratics may belong to nearly the same era as those 

 " refuse-heaps." But were we to go back to a long antecedent 

 epoch, or to that of the Belgian and British caves with their 



